Blender 2.76 Cycles texture baking strange artifacts
Usually, this happens when the two meshes are intersecting. Avoid this enabling the cage option into the bake panel and set a distance maybe 0.05 (5 cm) in your case should do fine.

A normal map has mostly a blue tint indicating the z direction that the faces are pointing towards, In your case, as the meshes are intersecting you get this strange variation of colors because sometimes the hires mesh is on one side of the low res mesh, sometimes is on the other side.

Creating a cage (and not choosing an object as a cage) is like inflating your low-resolution mesh and projecting towards inside from a certain distance to find the high res object. 

If you have a complicated shape and usually the concave shapes that simply "inflating" it makes it intersect with herself might need a cage object ( with the same number of verts as the low res object). 

Also, shade smooth your high-resolution object.

P.S. You might want also to give a bit more distance between the two UV islands as they might overwrite each other.